142 FRAGMENTS OF SCIENCE. 



sown in our atmosphere, the light scattered by those parti- 

 cles would be exactly such as we observe in our azure skies. 

 When this light is analyzed, all the colors of the spectrum 

 are found ; but they are found in the proportions indicated 

 by our conclusion. 



Let us now turn our attention to the light which passes 

 unscattered among the particles. How must it be finally 

 affected ? By its successive collisions with the particles, 

 the white light is more and more robbed of its shorter 

 waves ; it therefore loses more and more of its due propor- 

 tion of blue. The result may be anticipated. The trans- 

 mitted light, where short distances are involved, will appear 

 yellowish. But as the sun sinks toward the horizon the 

 atmospheric distances increase, and consequently the num- 

 ber of the scattering particles. They abstract in succession 

 the violet, the indigo, the blue, and even disturb the pro- 

 portions of green. The transmitted light under such cir- 

 cumstances must pass from yellow through orange to red. 

 This also is exactly what we find in Nature. Thus, while 

 the reflected light gives us at noon the deep azure of the 

 Alpine skies, the transmitted light gives us at sunset the 

 warm crimson of the Alpine snows. The phenomena cer- 

 tainly occur as if our atmosphere were a medium rendered 

 slightly turbid by the mechanical suspension of exceedingly 

 small foreign particles. 



Here, as before, we encounter our skeptical " as if" It 

 is one of the parasites of science, ever at hand, and ready 

 to plant itself and sprout, if it can, on the weak points of 

 our philosophy. But a strong constitution defies the para- 

 site, and in our case, as we question the phenomena, proba- 

 bility grows like growing health, until in the end the malady 

 of doubt is completely extirpated. The first question that 

 naturally arises is, Can small particles be really proved to 

 act in the manner indicated ? No doubt of it. Each one 

 of you can submit the question to an experimental test. 



